Aluminum

characteristics
magnesium - aluminum - silicon
B
aluminium
Ga

[Ne] 3s 2 3p 1
27
13
aluminium

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generally
name, symbol, ordinal number aluminum, aluminium, 13
series Metals
group, period, block 13 (IIIA), 3, p
appearance silvery
proportion at the Earth's shell 7.57%
atomically
atomic mass 26.981538
atomic radius (computed) 125 (118) pm
Kovalenter radius 118 pm
van the Waals radius -
Elektronenkonfiguration [Ne] 3s 2 3p 1
electrons per energy level 2, 8, 3
electron affinity 4.08-4.25 eV
1. Ionization energy 577.5 kJ/mol
2. Ionization energy 1816.7 kJ/mol
3. Ionization energy 2744.8 kJ/mol
4. Ionization energy 11577 kJ/mol
5. Ionization energy 14842 kJ/mol
6. Ionization energy 18379 kJ/mol
7. Ionization energy 23326 kJ/mol
8. Ionization energy 27465 kJ/mol
9. Ionization energy 31853 kJ/mol
10. Ionization energy 38473 kJ/mol
physically
state of aggregation (magnetism) firmly (paramagnetic)
crystal structure cubically face-centered
density (Mohshärte) 2700 kg/m 3 (2,75)
melting point 933.47 K (660.32 ° C)
boiling point 2740 K (2467 °C)
molecular volume 10,00 · 10 -6 m 3 /mol
heat of vaporization 293.4 kJ/mol
heat of fusion 10.79 kJ/mol
steam pressure 2,42 · 10,-06 Pa
speed of sound 5100 m/s with 293 K
specific thermal capacity 900 j (kg · K)
Electrical conductivity 37,7· 10 6 S /m
heat conductivity 237 w (m · K)
Warming and/or. Longitudinal strain 23,8·10 -6 K -1
elastic module 70000 N/mm ²
chemically
oxidation conditions of 3
oxides (basicity) (amphoter)
Normalpotenzial -1.662 V (aluminium 3+ + 3e - → aluminium)
Elektronegativität 1,61 (Pauling scale)
isotopes
isotope NH t 1/2 ZM CPU M eV ZP
25 aluminium {syn.} 7.183 s ε 4.277 25 mg
26 aluminium {syn.} 7,17 · 10 5 A ε 4.004 26 mg
27 aluminium 100% Aluminium is stably with 14 neutrons
28 aluminium {syn.} 2.2414 min β - 4.642 28 SI
29 aluminium {syn.} 6.56 min β - 3.680 29 SI
as far as possible and common, is used SI-UNITs.
If not differently notes,
the indicated applyData with standard conditions.

Aluminum (of lat. alumen = alum) is a chemical element of the periodic system with the ordinal number 13. The element symbol is aluminium It belongs to the group of boron (in former times also as group of the earth metals designates).

Aluminum is the third-most frequentElement and most frequent metal in the earth's crust and arise because of its reaction joyfulness only in chemical-bound condition.


Table of contents

characteristics

Aluminium
aluminum

the pure light alloy aluminum has due to one very fast at air forming thin oxide coating a blunt, silver-grey appearance. The oxide coating makes pure aluminum very corrosion resistant.By electrical oxidation (anodize) or on chemical way the protecting oxide coating can be strengthened.

Aluminum reacts violently with sodium hydroxide under formation of hydrogen. This reaction is used in chemical tubing cleaning agents. With bromine aluminum reacts at room temperature under flame feature. Here is to note that developing aluminum bromide reacts with water under formation of alumina and hydrobromic acid. With mercury aluminum under formation of an amalgam reacts.

Aluminum is a very soft, tough metal. It is flexible and can by rolling out toothin foil to be processed. It can be poured well, deforms, bends, presses, schmieden and to machine. Developed tensions by cold deforming can be eliminated by annealing (until 250 °C).

Aluminum is a good electrical conductor (the conductivity amounts to 60 per cent ofthat of the copper). With a transition temperature of 1,8K aluminum becomes superconducting.

In order to prove aluminum, one gives the appropriate connection on a magnesia gutter with approx. and this heats two drops up cobalt nitrate solution in the Bunsen burner. Is aluminum colors itself the gutter available after Thenards blue.

history

Plinius tells that once in the palace emperors Tiberius, that in the years 14 to 37 n. Chr. governed, a Metallarbeiter appeared, and a metallic gift offered, which looked outward like silver,but was remarkably easy. The emperor asked the worker, where this metal would be to be found and the answer received that that one would have made it of a tonhaltigen earth. Tiberius continued to ask whether otherwise still someone around the presence and thoseProduction of this metal would know, on which the worker answered to his mischief that except him only Jupiter knows the secret. The emperor however was seized of suspicions that the new metal could damage the value of the gold and the silver andtherefore the workshop of the gift giver let destroy and behead the same, so that the invention was lost. When Sir Humphry Davy discovered and described aluminum in the year 1808, one remembered again the fate of this unfortunate Metallarbeiters and it spreadthe opinion that it concerned with this sayful metal aluminum. Even if a true core would be in this narration, then it would be completely unsettled, like an individual worker the technical difficulties have overcome could,the aluminium production to overcome are. Only 1825 succeeded it to the Dane Hans Christian Ørsted aluminum, which does not occur in nature in gediegener form, to manufacture synthetically however in very contaminated form. The production of pure aluminum in powder form succeeded 1827the German chemist Friedrich better. At that time the price of aluminum was higher than from gold.

Henri Sainte Claire Deville refined the well-being he process in the year 1846 and published it 1859 in a book. Thus the aluminum price fellwithin ten years around 90 per cent.

1886 independently developed Paul Héroult the procedure for the production of aluminum, designated now after them, by Charles Martin resound and: the resound Héroult process. According to this principle this very day the industrial takes placeAluminum production. In the year 1889 the procedure was continued to improve by Carl Josef Bavarian.

occurrence

aluminum is the metal, which occurs in the earth's crust most frequently (7.57 per cent of the total weight of the earth's crust). It does not arise however gediegen,separate only in chemical compounds. One finds aluminum in nature frequently in Alumosilikaten as a component of e.g. Clay/tone, Gneis and granite.

An economic production of aluminum is possible only from bauxite. Bauxite contains approx. 60 per cent alumina (aluminium 2O 3), approx. 30 per cent ferric oxide (Fe 2 O 3), silicon oxide (SiO 2) and water.

In rare form alumina in corundum , well-known present as ruby and sapphire, is. The red or blue color of the stonesresults from impurities.

Bauxite occurrences are in Southern France (Les Baux), Hungary, Russia, India, Australia and the USA.

production and representation

in the procedure of Ørsted (1825) are made aluminum of aluminum chloride and potassium amalgam, whereby potassium as reducing agent serves:

<math> \ mathrm {AlCl_3 + 3K \ rightarrow aluminium + 3KCl}< /math>

After better metallic potassium is used for the reduction.

Technically the production of aluminum succeeds by fusion electrolysis (Kryolith alumina procedure, Bavarian procedure). Alumina is melted and elektrolysiert with Kryolith. Develops at thatCathode aluminum and at the anode oxygen.

The oxygen reacts with the coal anode to carbon dioxide and carbon mono oxide - which graphite blocks, which form, burn the anode and occasionally replaced. The coal cathode is inert opposite aluminum.

This process is very energieaufwändig. The energy expenditure amounts to about 13-16 kWh/kg. With this energy quantity for the production of a ton aluminum one could supply a single family house 2 years long.

Environmental federations criticize the employment of aluminum because of high resources consumption with thatProduction. The metal aluminum can be made only in principle on electro-chemical way of mineral raw materials.

use

ways of the small density of aluminum is used gladly this metal, where mass must be moved, particularly in thatPackaging industry and air and space travel. For this reason the material aluminum wins also in the construction of vehicles increasingly in meaning; Motor vehicle manufacturers use the advertising effect of the material. In alloys with magnesium, silicon and other metals strengtheningnesses in extruded sections are reached, thoseare inferior only little from steel. Therefore is the use of aluminum for the weight reduction much likes. In particular in the aircraft construction and in the space technology aluminum is the material of the choice. Aluminum is used in overhead power lines as pipe material - the small densityis here decisive. Copper lines with the same conductivity would have a smaller cross section, but a higher mass.

Because of the high heat conductivity aluminum becomes as material for e.g. Heat exchanger (radiator) and cooling fins use.

In the household one meets aluminum in the form ofBeverage doses and aluminum foil on, occasionally also as pots or as Campinggeschirr.

In the food production it finds to use as food color (E 173) with coats from sweets to the decoration of cakes and purifies baking goods.

In powder form (particle size < 500 µm) is itabove all, if it is not phlegmatisiert, due to its large surface very reactively. Thus aluminum reacts with water under delivery from hydrogen to alumina. Likewise it is essential for those strongly exotherms (up to 2500 °C) Thermit reaction. Caution: Not more phlegmatisierterAluminum-deaf catches fire with air contact automatically like an explosion, he has the Gefahrenzeichen [F+].

Articles from aluminum are protected frequently by an anodized coat.

The aluminum processing often happens by casting procedure (aluminum foundry).

Prototypes:

here one must differentiate between such procedures, which serve the production (nearly) manufacturer of construction units (e.g. Sand casting, pressure pouring, high quality casting) and such, which supply raw material for the subsequent treatment to semi-finished material such as sheet metals and extruded sections (e.g. Continuous casting). Sprühkompaktieren and volume casting take a privileged position.

The production of semi-finished material or construction units happens from starting material like e.g. Rolling ingot by reforming procedure

transforming:

exhibits extrusion rollers

Schmieden

[work on] in glowing with diluted cobalt nitrate solutionthe magnesia gutter after. The pigment Thénards blue develops (cobalt blue or cobalt blue, Dumonts blue, Coelestinblau, Leithners blue, cobalt aluminate). It is a cobalt aluminum spinel with the formula CoAl 2 O 4. This proof reaction became 1795 of Leithner by glowing of Aluminium sulfate and cobalt nitrate (CO (NO 3) 2) discover. The industrielle production by that Paris university professor Louis Jacques Thénard was arranged.

production chain

Bild:aluproduktionskette.jpg

aluminum alloys

aluminum can in the fusionliquid condition with copper, magnesium, manganese, Silicon, iron, titanium, beryllium, chrome, zinc, zircon and molybdenum to be alloyed, in order determined promote characteristics or others suppress undesired characteristics.

During most alloys however the education is the protecting oxide film(Passivation) strongly disturbed, woduch the construction units manufactured from it corrosion endangered are partly high-grade. Almost all high-strength aluminum alloys are affected by the problem.

typical “hardenable” aluminum forgeable alloys are: AlMgSi, AlCuMg, AlZnMg, AlZnMgCu, the first high-strength, hardenable aluminum alloyAlCuMg got 1907 the label name duralumin.

There are aluminum forgeable alloys (AW, English. wrought), for example AlMg4,5Mn, and aluminum cast alloys (AC ONE, English. cast). Aluminum cast alloys e.g. become. for light alloy wheels uses. Generally aluminum alloys become after the system of the AA (Aluminum Association) designates.

Here the following classification applies after the respective main alloying element to forgeable alloys:

a further number designates special alloys an x. Examples are about 2024, 5083 or 7075.

To cast alloys however the following classification applies:

connections

safety references

aluminum is not one of the few plentifully existing elements, a favourable function in living personsCells to have seem.

Aluminum is taken up by increasing acid load of the soils increased by the plants. We get daily on the average 25 mg aluminum with the food. If meals now still in the aluminum table-ware prepared (sour food loosens aluminum!) and inAluminum foil to be kept, can increase the admission by 2 - 3 subject.

Aluminum is contained in baking powder, white flour ( as bleaches), fusion cheese, Scheibletten as well as sourly inserted Gemüsekonserven, as anti-becoming lumpy means in Kaffeeweissern, salt and spices. Aluminum connections are in additionin toiletries (Deo, tooth paste), in medicines against hyperacidity (Antacida), failure means (kaolin, Attapulgite, Bolus) and in some Lipidsenkern (Aluminiumclofibrat), as well as in industrial issues from the production of aluminum, the paper, glass, porcelain and textile industry.

Aluminum can be involved in anemia, because itthe same memory proteins as iron occupies. It can impair the bone metabolism, favour Arthritis, complaints of the nervous system like e.g. Memory and language disturbances, Antriebslosigkeit and aggressiveness carry and lead in any case with the time to liver and kidney damages (on the other hand helps alsoa liver or a kidney program). Aluminum disturbs the metabolism of calcium, chrome, iron, Fluor, Kupfer, Magnesium, Phosphor, Silizium, Zink as well as the Vitamine B6 and D.

Furthermore the suspicion exists that aluminum cancer of the breast to promote could.

Some per cent of the population react to aluminum strongly allergisch - they suffer excursions in each possible form by using anti-transpiration products, digesting disturbances and inability to take up nutrients from the food which was cooked in aluminum pots, or vomiting and other one Symptoms of intoxication by taking aluminum-bearing medicines.

ecology

regarding the environmental impact is to be emphasized the good ecycling barness of aluminum. In addition through lightweight construction with aluminum materials (for example aluminum foam, extruded sections) mass is saved by mobile parts and vehicles, which for energy conservationapplication leads.

On the other hand for the electrolysis by aluminum very much electricity is needed. The exploitation of bauxite, which is won predominantly in the open mining, leads to environmental degradations such as rain forest clearing.

see also

Web on the left of

Commons: Aluminum - pictures, videos and/or audio files
Wiktionary: Aluminum - word origin, synonyms and translations
 

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